Table 2.

Synergism with beta-cypermethrin, matrine, and azadirachtin between SS and SB strains

Insecticides	population	χ2a	Slope ± SE	LC50 (µg L−1)	95% CL	SRb
Beta-cypermethrin	SS	2.36*	2.30 ± 0.51	0.21	0.17–0.30	–
	SB	2.14*	3.13 ± 0.58	1.65	0.73–2.15	–
Beta-cypermethrin + TPP	SS	1.95*	1.67 ± 0.36	0.10	0.09–0.18	2.05
	SB	3.01*	2.81 ± 0.42	0.31	0.25–0.66	5.29
Beta-cypermethrin + PBO	SS	0.94*	1.17 ± 0.27	0.20	0.17–0.28	1.02
	SB	1.64*	1.85 ± 0.42	0.83	0.59–1.28	1.98
Beta-cypermethrin + DEM	SS	1.26*	1.54 ± 0.32	0.08	0.07–0.15	2.67
	SB	0.92*	2.15 ± 0.41	0.33	0.26–0.59	4.92
Matrine	SS	0.83*	1.63 ± 0.38	0.43	0.42–0.65	–
	SB	1.20*	2.63 ± 0.47	2.55	2.30–4.16	–
Matrine + TPP	SS	2.67*	0.63 ± 0.21	0.19	0.16–0.27	2.24
	SB	3.55*	1.14 ± 0.32	1.14	0.94–1.41	3.86
Matrine + PBO	SS	3.47*	1.89 ± 0.54	0.15	0.13–0.19	2.86
	SB	6.24*	4.67 ± 0.36	0.61	0.40–0.71	4.18
Matrine + DEM	SS	2.47*	1.54 ± 0.39	0.18	0.17–0.20	2.29
	SB	1.69*	0.72 ± 0.24	0.83	0.58–0.93	3.07
Azadirachtin	SS	2.13*	3.34 ± 0.64	0.54	0.31–0.59	–
	SB	2.89*	0.88 ± 0.24	1.38	0.73–1.66	–
Azadirachtin + TPP	SS	3.44*	1.96 ± 0.41	0.25	0.19–0.35	2.16
	SB	3.53*	2.11 ± 0.38	0.42	0.28–0.56	3.28
Azadirachtin + PBO	SS	1.24*	2.99 ± 0.57	0.26	0.16–0.41	2.08
	SB	3.14*	1.36 ± 0.32	0.33	0.21–0.49	4.19
Azadirachtin + DEM	SS	3.68*	2.94 ± 0.39	0.24	0.12–0.38	2.25
	SB	2.86*	1.71 ± 0.51	0.52	0.37–0.63	2.65

^*Meant pass the χ² test.

^aPearson chi-square, goodness-of-fit test.

^bSR: synergistic ratio = LC₅₀ of insecticides/LC₅₀ of (synergist + insecticides).